The invention relates to a device or system for the disposal of liquid media, such as cooling-lubricating liquids containing production residue, such as chips from industrial processes, wherein these media can be returned via gutters and/or pipe lines to a return reservoir disposed above ground level and from there through a pipe line connected near the bottom to at least one collecting tank by means of at least one return pump.
In a known device of this type (EP Patent Publication EP 0 593 005 A1) the medium with production residue to be disposed of flows to the return reservoir from the collection place, which requires that the collection place be located sufficiently far above the ground level. However, it is often not possible to comply with this requirement in connection with production machinery wherein the liquid medium with the production residue runs off toward the bottom.
It is therefore an object of the invention to make feeding of the liquid media with production residue into the return reservoir possible even if the collection place is located below or only slightly above the ground level, so that an inflow into the return reservoir above ground level is not possible.
This object is attained according to preferred embodiments of the invention in a device of the type mentioned at the outset, in that the media can be fed from the collection place (s), guided through a gutter to a pipe line connected to the upper area of the return reservoir, which is made pressure-resistant and whose interior can be placed under reduced pressure by means of an evacuating device also connected to its upper area, and that at least one device which detects the level in the return reservoir and which has at least one switch element is provided in the return reservoir.
Because of the suction effect produced via the pipe line it is possible to dispose the gutter below or immediately above the ground level, so that the liquid media with the production residue can flow into the gutter.
A pressure-reducing valve inserted between the return reservoir and the evacuating device is used to protect the return reservoir in certain preferred embodiments of the invention.
In certain preferred embodiments of the invention, a filter is connected downstream of the evacuating device for protecting the environment from contaminants which are carried along.
The evacuating device can be advantageously designed as a bypass channel compressor or rotary piston blower or liquid vacuum pump according to various contemplated embodiments of the invention.
To allow an exact control of the return pump(s) as a function of the respective level of the media in the return reservoir, the device detecting the level of the media can have several switch elements reacting to different positions of the level according to certain preferred embodiments of the invention.
To allow a more exact adaptation of the conveyance to the collecting tank as a function of the amount of media generated, two pipe lines leading to the collecting tank, each containing a return pump, can be connected to the area near the bottom of the return reservoir, according to certain preferred embodiments of the invention.
The disposal of liquid media can also be simplified by means of a device of the type described, if the media originate in different collection places where liquid media with production residue are not necessarily collected simultaneously, according to certain preferred embodiments of the invention. For example, this is the case if the collection places are associated with different processing machines which can be operating simultaneously or individually.
This last mentioned feature can be achieved according to certain preferred embodiments of the invention in that several return reservoirs with upstream gutters and upstream pipe lines and downstream return pumps as well as devices detecting the level are provided, that an intermediate reservoir is respectively placed between the gutter and the pipe line, that the several return reservoirs are connected parallel to a single evacuating device, that a switchable closing valve is inserted into each pipe line connecting a return reservoir with the evacuating device and that a device detecting the level in each intermediate reservoir with at least one switch element is provided in each intermediate reservoir.
In case that large-grained production residue, which cannot be pumped, is expected, a comminuting device for large-grained production residue can be placed upstream of each intermediate reservoir, according to certain preferred embodiments of the invention.
The operation of the systems of the invention should be controlled in such a way that when liquid media with production residue occur in at least one collection place, for example if one of the associated processing machines is operating, the evacuating device is constantly operating. In this case the activation of the evacuating device can be triggered in that the switch element of a device detecting the level in an intermediate reservoir reacts to the liquid media with production residue collected in this intermediate reservoir. This reaction of the switch element can also trigger the opening of the closing valve which has been shut up to that time and is located in the pipe line connecting the associated return reservoir with the evacuating device. In this case the closing valves in the pipe lines between the other return reservoirs and the evacuating device remain closed and are only opened when the switch elements for the devices for detecting the level in the other intermediate reservoirs react. The closing valves are correspondingly shut again when the level in the intermediate reservoirs has been lowered sufficiently far that the switch elements no longer react.
The return pumps are correspondingly activated when a switch element disposed in the upstream connected return reservoir for detecting the level is actuated, and they are shut down again when a switch element of this device no longer reacts.
The switching process of closing the switch valves and the shut-off of the return pumps is triggered with different run-on times, so that the intermediate reservoirs and the return reservoirs are completely emptied or at least emptied as much as possible.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.